He can't sleep. The darkness of his room rattles around his bones. Feeds him recent memories: of Amara's mouth and the things she offered, and of Cas's limbs – their movement all wrong, body language uncanny. Artificial, like Esperanto. Beneath his eyelids, there's an imprint of sordid lips, of full and half revealed breasts. He nearly retches, he wants none of it, and yet his body is pulled towards it in a way he can't control. He feels dirty all the time, Amara a piece of broken glass stuck inside his shoe. Every step hurts, especially when he tries to walk away from her. He knows he'll dream of her once he falls asleep. Maybe this is why he doesn't want to. But it's definitely not why he can't.
No, that one's on Cas (it wouldn't be the first time).
Dean thinks of how earlier that day he instinctively kept his gun trained at Cas's back for a few seconds after he recognized it was him. He thinks how differently Cas moved, and how he shied away from the cold of his body. When Cas touched him, on the wrong shoulder, he ran cold. His usual warmth was gone. Gone from his eyes – the place that plenty of his smiles never reached. There was too much ease and familiarity to the way he moved – not like Cas, but like a cat: cunning and unafraid. In his eyes there wasn't the love that Dean always craved for so much, but pretended to look away each time. There was something methodical to the gaze, curiosity of blue eyes purely analytic. As if Dean was a peculiar specimen of something new. His voice sounded like a recording. And when Dean, with shame, confessed his sickening attraction to Amara, Cas didn't even flinch, while - by all accounts – he should have, because if there is one thing Dean knows for sure (and it hurts), it's that Cas is in love with him (tragically reciprocated, but that's never the point).
But there was nothing. This is how Dean knows Cas ain't Cas.
Come here, we need to talk – he texts.
There's the unmistakable rustle of wings, which only proves that it's not Cas. Cas's wings are done for.
"Who are you," Dean doesn't beat around the bush. He grits out the question, angel blade in hand.
"Why, Dean," comes a soft smile that curls around the gravel voice. "I'm the one who raised you from perdition."
Dean turns on the lights. Cas, or whatever it is, is white clad and staring at him in wild curiosity, with brightly painted amusement.
"I know Cas and you ain't him."
"And where does that come from?"
"You got all the details wrong, buddy," Dean smiles.
"Aww", the thing coos. "And your pretty little heart knows better? You're so cute I could eat you, sunshine," it licks Cas's lips with a forked tongue.
"What have you done to Cas," Dean snarls.
"Nothing he didn't agree on, baby doll. He was just tired. I let him sleep."
"Tired of what," Dean insists, somehow this is important.
"Of you not being there for him, mostly."
"That's bullshit."
"Only the sad people let me in, kitten. Only those who want to stop suffering. Those who want to be useful just once. Does that sound like our dear Castiel to you? Or does it sound like your brother in the past – in the one you never called him back?"
"Lucifer," Dean spits, terrified. Not of the devil, but of Cas's decision. What damage could he possibly fucking have to make such a stupid choice?
"I don't know why you're surprised, Dean," Lucifer sighs. "I have already told you once that we would always end up here. You just altered a few details, is all." This time the devil really smiles and it pisses the holy shit out of Dean.
"What do you mean: end up here? You're still not wearing Sam to prom."
"No, Dean. I'm wearing the person you love the most, just like I have before. It's just that the person has changed. But like I said, that's simply details."
"That's not just details to me," Dean says, eyes wide from anger and disbelief. Apparently, he's said damage.
"You wanna know why Sam said yes? Why Castiel did? Because, buddy, this is something you can thank yourself for."
"Shut up."
"Why? You told me to come here because we needed to talk. So let's talk, Ken Doll," Lucifer's expression hardens.
"Not about this."
"So you don't wanna find out why your boyfriend said yes to me before he could ever say yes to you? Oh right! That's why! Because he could never have a yes from you!"
"Fuck you, that's not true," Dean says, but he knows it's a lie as fast as it escapes his mouth. He never gave Cas a single sign, he pushed him away at every occasion – because he was too afraid, because he didn't think he was worth it. Even now the words "I love him" get stuck behind Dean's teeth. He swallows them. "Fuck you," he repeats flatly, there's no ire to it. "I tried to show it all the time. I thought he could see."
"Like you've shown him when you kicked him out or when you punched him half to death?" Satan asks innocently. "Or when I was taking care of him in the cage and you were licking Sammy's wounds?"
"You're taking shit out of context,"
"A heart doesn't need a context, Dean," Lucifer points out. "Imagine what he felt when you told me you have the hots for our favorite young lady."
"Why are you doing this?" Dean asks, genuinely confused.
"Because I want you to know he's no longer yours. He's mine," he chirps.
"Cas," Dean tries. "Come on. Come back, we can fix this." To no avail. Lucifer snorts.
"He can't hear you, you know. He doesn't want to."
"That's not true," Dean hisses. "Cas! Cas!"
"Try harder maybe?"
"I love you," Dean says finally and his whole body sags. He feels thirty years older.
"Fun fact: when he was told to kill you, a dummy version of you said that three hundred times. And he still killed you."
"Cas, what do you want me to say?" he says, resigned.
"At this point, buddy? Nothing. He wants nothing. Love of one man can't fix so many broken bones."
"Cas, let me try," Dean begs, eyes watery.
"Oh," Satan says intrigued. "You touched his feelings. And all two of mine."
"Cas, you hear me!? I'm gonna save you!"
Lucifer comes closer, the tips of his shoes touch Dean's feet. "No, you won't," he says and kisses Dean, startling him. "This time you will watch him destroy the world." He laughs. "Darkness rode within you and light now rides within him, isn't that poetic? He looked at you back then and knew that he lost you. Now you'll look at me and know that you lost him," he hums.
"Fuck you," Dean mutters hopelessly.
"Who knows? One day I might want to," Lucifer chuckles darkly. "Be careful what you wish for, Dean. I'll be listening to both of you scream. We'll have a gay old time."
"Cas, for the love of fuck, I will find a way," Dean tries, but the devil cuts him off.
"There was a way. You just should have loved him more," he says. "But you're a hero with no balls."
"I'm sorry, Cas. I was afraid," Dean whispers. Lucifer cups his cheek. His palm is cold.
"You don't know fear yet," he murmurs, kissing his temple. "I'll fix that," he promises. "You're gonna pray for the Darkness to gulp in your soul soon," he adds. "Goodnight, Dean," he kisses him once more, and with that, he disappears.
Dean already wants that. He doesn't want to feel a thing. He feels everything now and it hurts. Every small thing he never said to Cas and all the vile things that he did find the time to say. All the silences that stretched out for miles between them and he breathed through them like a coward. He hoped that it would go away on both sides eventually, but how stupid he was to hope? He was aware of the magnitude of Cas's love and yet he's done nothing with it, nothing to even acknowledge it. He deserves for Amara to devour him. He hopes she will before Lucifer does. He does hope she'll take him into her filthy oblivion soon. They're both dirt, after all.
But first, he needs to save Cas from perdition.